Multi-base material adaptivity pulling removal type binder product, binder composition and assembly

ABSTRACT

The present disclosure provides a multi-base material adaptivity pulling removal type binder product, a binder position and an assembly. The binder product contains an acrylic acid copolymer, a flexibilizer, tackifying resin and an isocyanate curing agent. The binder product comprises a binder layer formed by curing at least a part of the binder composition. The assembly is formed by bonding the binder layer. The binder can be used for firmly bonding various base materials, comprising both high surface energy base materials and low surface energy base materials; meanwhile, the binder can be pulled and removed from the base materials at a large angle. The binder is particularly suitable for the fields of smartphones, tablet computers and a newly developing electronic market.

FIELD

The present disclosure relates to a binder. Particularly, the presentdisclosure relates to a multi-base material adaptivity pulling removaltype binder product, a binder composition capable of being used forpreparing the binder product and an assembly formed by bonding.

BACKGROUND

Although the condition that the performance of a binder can be improvedby using a tackifier and a thickener is a known fact, and respectivecomponents of a binder formula are possibly known, but aiming at thespecifically required final use requirements, the problem of how toselect combination of specific binder components and relative quantitythereof still faces great challenge, which is caused by the fact thatbalance of required performances is very difficult to achieve.

In the technical field of the binder formula, the requirement ofrealizing a bonding action aiming at various base materials alwaysexists, and the base materials comprise base with low surface energy andbase materials with high surface energy. Although existing binders canprovide proper performances aiming at certain base materials, but morechoices are still required actually to meet certain criticalrequirements. For example, in some application occasions, it is requiredthat the binder should have better adaptivity to both the base materialswith low surface energy and the base materials with high surface energy(namely, multi-base material adaptivity). Besides, in certainapplication occasions, it is hoped that the binder can be removed bypulling, which requires that the bonding strength intensity of thebinder can be obviously reduced while the binder is pulled along thebonded base material. In home furnishing, electronic, industrial andother fields, an application requirement on such multi-base materialadaptivity pull removal type binders exists.

In application of electronics industry (particularly smartphones andtablet computers), there are also some new requirements. In suchapplication, various base materials to be bonded are related, arepossibly subject to different surface treatments, have high or lowsurface energy and have the characteristic of ultrathin thickness. Forthese applications, the key requirements comprise: the binder can bereliably removed through vertical pulling, and has bettermoisture/heat/aging resistance at the same time. The constituting andstructures of the binders in the prior art hardly meet the newapplication requirements in the electronics industry.

Therefore, a new selectable binder is needed.

SUMMARY

The present disclosure provides a multi-base material adaptivity pullingremoval type binder product, a binder composition capable of being usedfor preparing the binder product and an assembly formed by bonding. Thebinder product can be used for firmly bonding various base materials,and can be pulled and removed from the base materials at large angles,namely, the binder has the physical property of “reducing bondingstrength by pulling”, so the binder can be removed from the bonded basematerials by pulling. In addition, the binder has the performance ofobviously improving damp/heat/aging resistance. The pulling removalbinder is widely applied in home furnishing, electronic, industrial andother fields, and is particularly suitable for the applicationrequirements of smartphones, tablet computer and newly-developingelectronic markets, for example, can be used for mounting and detaching(repairing or replacing) of batteries or electronic parts (such as atouch screen).

In one aspect, the present disclosure provides a binder composition,comprising: an acrylic acid copolymer, comprising a (methyl)acrylatemonomer unit and a vinyl carboxylic acid comonomer unit; a flexibilizer,comprising a functional group selected from a hydroxide radical, acarboxyl group and an amino group, wherein the flexibilizer has anon-polar carbon chain; a tackifying resin, comprising a high-Tgtackifying resin with a Tg of at least 20° C. and a low-Tg tackifyingresin with a Tg of not more than 0° C.; and an isocyanate curing agent.In some embodiments, a number average molecular weight Mn of the acrylicacid copolymer is lower than 500,000 g/mol and the Tg is lower than −30°C.

In some embodiments, the acrylic acid copolymer comprises the vinylcarboxylic acid copolymer unit in the amount ranging from 3 wt % to 8 wt%. In some embodiments, the binder composition comprises the acrylicacid copolymer in the amount ranging from 20 wt % to 50 wt %. In someembodiments, the non-polar carbon chain of the flexibilizer is derivedfrom unsaturated alkene.

In some embodiments, the flexibilizer comprises the combination ofhydroxy-terminated polybutadiene and SBS rubber. In some embodiments, ahydroxyl content of the hydroxy-terminated polybutadiene is at least 1mmol/g. In some embodiments, a number average molecular weight Mn of thehydroxy-terminated polybutadiene is between 2300 g/mol and 4500 g/mol.

In some embodiments, the hydroxyl-terminated polybutadiene is present inan amount ranging from 20 wt % to 50 wt % based on the weight of theacrylic acid copolymer. In some embodiments, the binder compositioncomprises the SBS rubber in an amount ranging from 5 wt % to 35 wt %. Insome embodiments, the binder composition comprises the flexibilizer inan amount of not more than 65 wt %. In some embodiments, the bindercomposition comprises the flexibilizer in an amount ranging from 10 wt %to 65 wt %.

In some embodiments, the Tg of the high-Tg tackifying resin is at least85° C. and the Tg of the low-Tg tackifying resin is not more than −20°C. In some embodiments, a weight ratio of the high-Tg tackifying resinto the low-Tg tackifying resin ranges from 1:1 to 8:1. In someembodiments, a weight ratio of the high-Tg tackifying resin to thelow-Tg tackifying resin ranges from 2:1 to 4:1. In some embodiments, thebinder composition comprises the tackifying resin in an amount rangingfrom 30 wt % to 45 wt %.

In some embodiments, the isocyanate curing agent is present in an amountranging from more than 0 wt % to not more than 3 wt % based on theweight of the acrylic acid copolymer. In some embodiments, theisocyanate curing agent is present in an amount of at least 5 wt % basedon the weight of the hydroxy-terminated polybutadiene.

In some embodiments, the binder composition comprises: the acrylic acidcopolymer in an amount ranging from 20 wt % to 50 wt %, the flexibilizerin an amount ranging from 10 wt % to 65 wt %, the tackifying resin inthe amount ranging from 30 wt % to 45 wt %, and the isocyanate curingagent in the amount ranging from more than 0 wt % to not more than 3 wt% based on the weight of the acrylic acid copolymer.

In another aspect, the present disclosure provides a binder product,comprising a binder layer formed by curing at least a part of the bindercomposition in any one of aforementioned embodiments. In someembodiments, the binder product further comprises: a carrier, whereinthe binder layer is disposed on one side of the carrier, or the binderlayers are respectively disposed on two opposing sides of the carrier;and an isolation layer optionally covering an exposed surfaced of thebinder layer. In some embodiments, the carrier contains an elastomerwith a non-polar carbon chain. In some embodiments, the elastomer isselected from SBS, SEPS, SIS and isocyanate-crosslinkedhydroxy-terminated polybutadiene.

In some embodiments, when a test is performed according to an initialviscosity test standard PSTC-6, a ratio of an initial viscosity of thebinder product under a non-pulling state to an initial viscosity whenthe binder product is pulled to a strain of 300% is more than 3. In someembodiments, when a test is performed according to an initial viscositytest standard PSTC-6, a ratio of an initial viscosity of the binderproduct under a non-pulling state to an initial viscosity when thebinder product is pulled to a strain of 300% is more than 5.

In some embodiments, after being aged for 72 hours under the conditionof 65° C. and relative humidity of 95%, a test is performed according toan initial viscosity test standard PSTC-6, and a ratio of an initialviscosity of the binder product under a non-pulling state to an initialviscosity when the binder product is pulled to a strain of 300% is morethan 2.4. In some embodiments, after being aged for 72 hours under thecondition of 65° C. and relative humidity of 95%, a test is performedaccording to an initial viscosity test standard PSTC-6, and a ratio ofan initial viscosity of the binder product under a non-pulling state toan initial viscosity when the binder product is pulled to a strain of300% is kept more than 5.

In another aspect, the present disclosure provides a method forpreparing a binder product, comprising following steps: providing thebinder composition according to any one of aforementioned embodimentspositioned in a liquid medium, and obtaining a coating liquid; coatingthe coating liquid on one side or two opposite sides of a carrier, andforming a coating; and curing at least a part of the coating and forminga binder layer. In some embodiments, the liquid medium is selected froman organic inert solvent and the carrier comprises an elastomer with anon-polar carbon chain.

In yet another aspect, the present disclosure provides an adhesive tape,comprising: a carrier containing an elastomer, and a binder layerdisposed on one side or two opposing sides of the carrier, the binderlayer is formed by the binder composition and the binder compositioncomprises: an acrylic acid copolymer in an amount ranging from 20 wt %to 50 wt %, comprising a (methyl)acrylate monomer unit and a vinylcarboxylic acid comonomer unit in an amount ranging from 3 wt % to 8 wt%; a flexibilizer in an amount ranging from 10 wt % to 65 wt %,comprising a combination of hydroxy-terminated polybutadiene and SBSrubber; a tackifying resin in an amount ranging from 30 wt % to 45 wt %,comprising a high-Tg tackifying resin with a Tg of at least 20° C. and alow-Tg tackifying resin with a Tg of not more than 0° C., wherein aweight ratio of the high-Tg tackifying resin and the low-Tg tackifyingresin ranges from 1:1 to 1:8; and an isocyanate curing agent, whereinthe isocyanate curing agent is present in an amount of not more than 3wt % of the weight of the acrylic acid copolymer and in an amount thatis least 5 wt % of the weight of the hydroxy-terminated polybutadiene.

In some embodiments, the acrylic copolymer has a number averagemolecular weight Mn lower than 500,000 g/mol and a Tg lower than −30° C.In some embodiments, a hydroxyl content of the hydroxy-terminatedpolybutadiene is between 1 mmol/g to 1.5 mmol/g, number averagemolecular weight ranges from 2300 g/mol to 4500 g/mol, and thehydroxyl-terminated polybutadiene is present in an amount ranging from20 wt % to 50 wt % based on the weight of the acrylic acid copolymer;wherein the binder composition comprises the SBS rubber in an amountranging from 5 wt % to 35 wt %. In some embodiments, the Tg of thehigh-Tg tackifying resin is at least 85° C. and the Tg of the low-Tgtackifying resin is not more than −20° C., and a weight ratio of thehigh-Tg tackifying resin to the low-Tg tackifying resin ranges from 2:1to 4:1. In some embodiments, the elastomer is selected from SBS, SEPS,SIS and isocyanate-crosslinked hydroxy-terminated polybutadiene.

In still another aspect, the present disclosure provides an assembly,comprising a first base material, a second base material and a binderlayer for bonding the first base material and the second base materialtogether, wherein the binder is formed by curing at least a part of thebinder composition according to any of the aforementioned embodiments.In some embodiments, the first base material and the second basematerial are respectively independently selected from low surface energybase materials with a surface energy ranging from 20 dyne to 35 dyne andhigh surface energy base materials with a surface energy higher than 35dyne. In some embodiments, the first base material and the second basematerial are respectively independently selected from metal, ceramic,polymer, glass and ink surface. In some embodiments, the binder layercan be removed from the first base material and/or the second basematerial by pulling.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of one embodiment of a binder product ofthe present disclosure.

FIG. 2 is a schematic diagram of a device for testing anti-fallingperformance of the present disclosure.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure provides more detail in combination with drawingsand specific embodiments. These embodiments are exemplary and intendedto describe the present disclosure in manner allowing those skilled inthe art to understand the present disclosure, but details thereof shouldnot be understood as limiting the present disclosure.

Binder Composition

The binder composition of the present disclosure contains an acrylicacid copolymer, a flexibilizer, tackifying resin and an isocyanatecuring agent.

Acrylic Acid Copolymer

The acrylic acid copolymer capable being used for the present disclosurecontains a (methyl)acrylate monomer unit and a vinyl carboxylic acidcomonomer unit.

The term “copolymer” refers to a copolymer formed by copolymerization ofat least two different monomers, comprising a random copolymer, asegmented copolymer, a grafted copolymer, an alternating copolymer or amixture thereof.

The term “(methyl)acrylate” refers to acrylate and/or methacrylate.

The term “monomer unit” refers to a largest structural unit formed bysingle monomer molecules in a copolymer structure.

The terms “binder” and “binder composition” are used hereininterchangeably.

The number average molecular weight Mn of the acrylic acid copolymer isusually lower than 500,000, preferably lower than 400,000 and morepreferably in a range of 250,000-350,000. Tg of the acrylic acidcopolymer is preferably lower than −30° C. and more preferably lowerthan −35° C. Tg refers to glass-transition temperature and can bedetected by a differential scanning calorimetry (DSC) method.

The acrylic acid copolymer capable of being for the present disclosurecomprises those acrylate-vinyl carboxylic acid copolymers, which areusually used for a binder and can be prepared according to a document,for example, the acrylic acid copolymer described in US 2011/0104486,and can be commercially available, for example, from SK-Dyne® 1717 DT ofcompany Soken Kagaku.

Some exemplary (methyl)acrylates capable of being for preparing theacrylic acid copolymer of the present disclosure comprise but are notlimited to (methyl) acrylic acid alkyl ester. The term “alkyl” refers toa monad group of alkane, and can be linear, branched, and cyclic orcombination thereof, and usually has 1-20 carbon atoms. In someembodiments, the alkyl contains 1-18, 1-12, 1-10, 1-8, 1-6 or 1-4 carbonatoms. Examples of the alkyl comprise but are not limited to: methyl,ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, t-butyl, n-amyl,n-hexyl, cyclohexyl, n-heptyl, n-octyl and ethylhexyl.

Some exemplary vinyl carboxylic acids capable of being for preparing theacrylic acid copolymer of the present disclosure comprise but are notlimited to acrylic acid, methacrylic acid, itaconic acid, maleic acid,fumaric acid and acrylic acid-β-carboxyl ethyl ester. Generallyspeaking, the acrylic acid copolymer of the present disclosure containsthe vinyl carboxylic acid comonomer unit of at least 3 weight % (wt %)or at least 4 wt %. Usually, the acrylic acid copolymer of the presentdisclosure contains the vinyl carboxylic acid comonomer unit which isnot more than 10 wt %, even not more than 8wt %, or not more than 5 wt%. Preferably, the acrylic acid copolymer of the present disclosurecontains the vinyl carboxylic acid comonomer unit of 3-8 wt %.

The binder composition can contain the acrylic acid copolymer of 20-50wt %. For example, calculated relative to the weight of the bindercomposition, the quantity of the acrylic acid copolymer can be 20 wt %,25 wt %, 30 wt %, 35 wt %, 40 wt %, 45 wt % or 50 wt %.

Flexibilizer

The flexibilizer capable of being used for the present disclosurecontains a functional group selected from a hydroxide radical, acarboxyl group and an amino group (these functional groups are all polarfunctional groups) and has a non-polar carbon chain. Preferably, thefunctional group is positioned at the terminal of a molecular chain ofthe flexibilizer.

The term “non-polar carbon chain” refers to a polymer chain which takesa carbon chain formed by a plurality of connected carbon atoms as abasic structure and contains no polar functional groups or side chains.The non-polar carbon chain of the flexibilizer is preferably derived andselected from unsaturated alkenes, such as butadiene, ethylene,pentadiene or combination thereof.

In the present disclosure, besides the function of improving thetenacity of a cured product, the flexibilizer also achieves a bridgingagent. Molecular polarity has great influence on substancedissoluvability. Polar molecules are easily dissolved in polar solventsand non-polar molecules are easily dissolved in non-polar solvents,namely, “similarity and intermiscibility”. Wherein, the flexibilizer hasa non-polar carbon chain, and thus can be better compatible with othernon-polar components in the composition. If the flexibilizer alsocomprises styrene-butadiene-styrene (SBS rubber), the non-polar carbonchain of the flexibilizer can be better compatible with SBS rubber.Meanwhile, since the flexibilizer contains the functional group selectedfrom the hydroxide radical, the carboxyl group and the amino group (forexample, a terminated functional group), the flexibilizer can react witha crosslinking agent and can be chemically combined in a polyacrylicacid system.

Preferably, the flexibilizer contains combination of hydroxy-terminatedpolydiene (particularly hydroxy-terminated polybutadiene, namely HTPB)and polystyrene-butadiene-styrene (SBS rubber).

The hydroxyl content of the hydroxy-terminated polydiene (such as HTPB)is preferably at least 1 mmol/g. Generally, the hydroxyl content ofhydroxy-terminated polydiene (such as HTPB) is not more than 1.5 mmol/g.The term “hydroxyl content” refers to the mole number of hydroxyl groupscontained in resin per gram.

The number average molecular weight Mn of the hydroxy-terminatedpolydiene (such as HTPB) is preferably 2300-4500, for example, about2500, 2800, 3000, 3500, 4000.

The hydroxy-terminated polydiene may be commercially available, forexample, under the trade designation “Qilong HTPB” from Qilong ChemicalCo., Ltd. Calculated relative to the weight of the acrylic acidcopolymer, the quantity of the hydroxy-terminated polydiene (such asHTPB) can be 20-50 wt %, for example, 20 wt %, 25 wt %, 30 wt %, 35 wt%, 40 wt %, 45 wt % or 50 wt %.

The SBS rubber can be commercially available, for example, under thetrade designation “Kraton D1101K” from the company Kraton, whichcontains a polystyrene block of about 16 wt % and contains a diblock ofabout 31 wt %. The binder composition can contain SBS rubber of about5-35 wt %. For example, calculated relative to the weight of the bindercomposition, the quantity of the SBS rubber can be 5 wt %, 10 wt %, 15wt %, 20 wt %, 25 wt %, 30 wt %, 35 wt %.

In the binder composition of the present disclosure, the total quantityof the flexibilizer is not more than 65 wt %. Preferably, the bindercomposition contains the flexibilizer with the total quantity between 10and 65 wt %. For example, calculated relative to the weight of thebinder composition, the total quantity of the flexibilizer is 10 wt %,15 wt %, 20 wt %, 25 wt %, 30 wt %, 35 wt %, 40 wt %, 4 5wt %, 50 wt %,55 wt %, 60 wt %, 65 wt %.

Tackifying Resin

The tackifying resin capable of being used for the present disclosurecontains high-Tg tackifying resin with Tg being at least 20° C. andlow-Tg tackifying resin with Tg being not more than 0° C.

The high-Tg tackifying resin has Tg of at least 20° C., and thus isusually solid at room temperature, preferably, the Tg is at least 40° C.or 60° C., and more preferably 85° C. or higher. Exemplary high-Tgtackifying resin comprises terpene, aliphatic series or aromaticseries-modified hydrocarbons with 5-9 carbon atoms and abietate. In someembodiments, as the compatibility with the acrylic acid copolymer isreduced along with the increment of the molecular weight of thehydrocarbons, the hydrocarbons with a lower molecular weight can bepreferably selected. In some embodiments, the weight mess averagemolecular weight Mw of the high-Tg tackifying resin is between 500 and2000. The weight average molecular weight of the high-Tg tackifyingresin in some embodiments is not more than 1500, is not more than 1000in some embodiments and even not more than 800 in some embodiments.

The low-Tg tackifying resin has Tg which is not more than 0° C., forexample, not more than −10° C. or even not more than −20° C. Generallyspeaking, as the compatibility with the acrylic acid copolymer isreduced along with the increment of the molecular weight, compounds withlower molecular weight can be preferably selected. Exemplary low-Tgtackifying resin comprise terpene phenolic resin, terpene, aliphaticseries or aromatic series-modified hydrocarbons with 5-9 carbon atomsand abietate. In some embodiments, the weight mess average molecularweight Mw of the low-Tg tackifying resin is between 300 and 1500. Theweight average molecular weight Mw of the low-Tg tackifying resin insome embodiments is not more than 1000, is not more than 800 in someembodiments and even not more than 500 in some embodiments.

Preferably, in the binder composition, weight ratio of the high-Tgtackifying resin to the low-Tg tackifying resin is 1:1 to about 8:1,more preferably 2:1 to 4:1. The binder composition contains thetackifying resin with the total quantity in a range of 30-45 wt %. Forexample, calculated relative to the weight of the binder composition,the total quantity of the tackifying resin is 30 wt %, 35 wt %, 40 wt %,45 wt %.

Curing Agent

The curing agent capable of used for the present disclosure is anisocyanate curing agent. The isocyanate curing agent comprises thosecuring agents with at least 2 isocyanate functional groups generallyused in the art, for example, diisocyanate and triisocyanate. Forexample, proper diisocyanate examples comprise aromatic diisocyanate,for example 2,6-toluene diisocyanate, 2,5-toluene diisocyanate,2,4-toluene diisocyanate, metaphenylene-toluene diisocyanate,p-phenylene diisocyanate, methylene bis(o-chlorphenyl diisocyanate),methylene diphenylene-4,4′-diisocyanate, polycarbodiimide-modifiedmethylene diphenylene diisocyanate,(4,4-diisocyanato-3,3′,5,5′-tetraethyl)diphenylmethane,4,4-diisocyanato3,3′-dimethoxy biphenyl(o-dianisidine diisocyanate),5-C1-2,4-toluene diisocyanate and 1-chloromethyl-2,4-diisocyanatobenzene, aromatic-aliphatic diisocyanate (for example, m-xlylenediisocyanate and tetramethyl-m-xlylene diisocyanate), aliphaticdiisocyanate (for example, 1,4-diisocyanato butane, 1,6-diisocyanatohexane, 1,12-diisocyanato dodecane and 2-methyl-1,5-diisocyanatopentane) and cyclic aliphatic diisocyanate (for example, methylenedicyclohexylidene-4,4-diisocyanate, 3-diisocyanatomethyl-3,5,5-trimethyl cyclohexyl isocyanate (isophorone diisocyanate)and cyclohexylidene-1,4-diisocyanate).

In the binder composition of the present disclosure, the curing agentprovides the crosslinking of the acrylic acid copolymer and theflexibilizer (for example, the hydroxy-terminated polybutadiene). Uselevel of the curing agent is determined according to specificapplication requirements and systems, generally speaking, if thequantity of the curing agent is too much, self-crosslinking of theacrylic acid copolymer is caused; otherwise, if the quantity of thecuring agent is too less, polar functional groups of the flexibilizer(for example, hydroxy groups of the hydroxy-terminated polybutadiene)are left, which results in decrease of viscosity of the system.Therefore, the quantity of the curing agent should be the quantitycapable of effectively curing the binder composition. In the bindercomposition, calculated relative to the weight of the acrylic acidcopolymer, the quantity of the isocyanate curing agent is generally notmore than 3 wt %, for example, 1 wt %, 1.25 wt %, 1.5 wt %, 2 wt %, 2.5wt %, 3 wt %. Relative to the weight of the flexibilizer containing thepolar functional groups selected from hydroxyl groups, carboxyl groupsand amino groups (for example, the hydroxy-terminated polybutadiene),the quantity of the isocyanate curing agent is usually at least 5 wt %.

The binder composition of the present disclosure can optionally containother additives, such as white pigment and the like which depends on anapplication condition.

In one embodiment, the binder composition of the present disclosurecontains: the acrylic acid copolymer of 20-50 wt %, the flexibilizerwith the total quantity being not more than 65wt % (preferably 10-65 wt%), the tackifying resin with the total quantity being 30-45wt % and theisocyanate curing agent with the quantity being capable of effectivelycuring the composition (preferably from 0 to not more than 3 wt % of theweight of the acrylic acid copolymer). Preferably, the flexibilizercontains the combination of hydroxy-terminated polybutadiene and SBSrubber, the quantity of the hydroxy-terminated polybutadiene ispreferably 20-50 wt % of the weight of the acrylic acid copolymer, theSBS rubber is preferably 5-35 wt % of the weight of the bindercomposition, and the quantity of the isocyanate curing agent ispreferably at least 5 wt % of the weight of the hydroxy-terminatedpolybutadiene.

Binder Product and Preparation Method

The binder product of the present disclosure comprises a binder layerformed by curing at least a part of the binder composition of thepresent disclosure. Common curing conditions in the art can be adopted,through certain temperature and time, isocyanic acid radicals in theisocyanate curing agent react with reactive functional groups in thesystem such as the hydroxyl groups/carboxyl groups/amino groups to formcarbamate/amide/carbamido groups, thereby, polymer chains are at leastpartially crosslinked, and the composition is cured.

The binder product can comprise a carrier for carrying the binder layer,the binder layer is carried on one side of the carrier, or the binderlayers are respectively carried on two opposite sides of the carrier.The carrier can contain an elastomer with a non-polar carbon chain, forexample, SBS, polystyrene-ethylene-butadiene-styrene (SEPS) elastomerand/or polystyrene-isoprene-styrene (SIS) elastomer,isocyanate-crosslinked HTPB.

The binder product can also comprise an isolation layer, and theisolation layer covers the exposed surface of the binder layer. In thisway, when not in use, the isolation layer can achieve an action ofprotecting the binder layer; while when in use, the isolation layer canbe peeled to expose the binder layer thereunder.

The isolation layer can use any proper isolation lining. Proper examplesof the isolation lining comprise paper, such as release paper (forexample, PCK release paper coated with polyethylene) or polymer film,for example polyethylene, polypropylene or polyester. At least onesurface of the lining can be treated by a parting agent (for example,organosilicone, fluoride-containing polymer and other isolationmaterials with low surface energy), thus forming the isolation lining.

Tested by an initial viscosity test standard PSCT-6, ratio of theinitial viscosity under a non-pulling state of the binder to the initialviscosity when the binder is pulled to a strain of 300% of the presentdisclosure is more than 3, preferably more than 5 and even 6 or 7 orhigher.

After being aged for 72 hours under the condition of 65° C. and relativehumidity of 95%, the binder of the present disclosure is testedaccording to the initial viscosity test standard PSCT-6, the ratio ofthe initial viscosity of the binder under the non-pulling condition tothe initial viscosity of the binder when being pulled to the strain of300% is more than 2.4, preferably more than 5 and even 6 or 7 or higher.

The binder product of the present disclosure can be in a single face ordouble face adhesive tape manner.

In one embodiment, the adhesive tape of the present disclosure comprise:a carrier containing an elastomer, and a binder layer positioned at oneside or two opposite sides of the carrier, the binder layer is formed bya binder composition and the binder composition contains:

-   -   an acrylic acid copolymer of 20-50 wt %, containing a        (methyl)acrylate monomer unit and a vinyl carboxylic acid        comonomer unit of 3-8 wt %;    -   a flexibilizer of 10-65 wt %, containing combination of        hydroxy-terminated polybutadiene and SBS rubber;    -   a tackifying resin of 30-45 wt %, containing high-Tg tackifying        resin with Tg being at least 20° C. and low-Tg tackifying resin        with Tg being not more than 0° C., wherein the weight ratio of        the high-Tg tackifying resin and the low-Tg tackifying resin is        1:1 to 1:8; and    -   an isocyanate curing agent, wherein the quantity of the        isocyanate curing agent is not more than 3 wt % of the weight of        the acrylic acid copolymer and is at least 5 wt % of the weight        of the hydroxy-terminated polybutadiene.

Preferably, the number average molecular weight Mn of the acrylic acidcopolymer is lower than 500,000 and Tg is lower than −30° C.

Preferably, the hydroxyl content of the hydroxy-terminated polybutadieneis 1-1.5 mmol/g, the number average molecular weight Mn is 2300-4500 andcalculated relative to the weight of the acrylic acid copolymer, thequantity of the hydroxy-terminated polybutadiene is 20-50 wt %.

Preferably, the binder composition contains the SBS rubber of 5-35 wt %.

Preferably, Tg of the high-Tg tackifying resin is at least 85° C., theTg of the low-Tg tackifying resin is not more than −20° C., and theweight ratio of the high-Tg tackifying resin and the low-Tg tackifyingresin is preferably 2:1 to 4:1.

Preferably, the elastomer is selected from SBS, SEPS, SIS, andisocyanate-crosslinked hydroxy-terminated polybutadiene.

FIG. 1 shows a schematic diagram of one embodiment of the binder productof the present disclosure. The binder product comprises a carrier 1,binder layers 2 positioned at upper and lower sides of the carrier 1 andan isolation layer 3 covering the binder layer 2.

The present disclosure also provides a method for preparing the binderproduct, which comprises the following steps: providing the bindercomposition of the present disclosure positioned in a liquid medium, andobtaining coating liquid; coating the coating liquid on one side or twoopposite sides of the carrier, and forming a coating; and curing atleast a part of the coating and forming a binder layer.

The liquid medium can be any proper solvent, and is commonly an organicinert solvent, namely, an organic solvent which does not react with anycomponent in the binder composition, and examples thereof comprise butare not limited to methylbenzene. The solid content of the coatingliquid is determined according to a formula of the binder and thecoating method, and is usually within a range of 10-50 wt %, and moretypically 20-40 wt %, for example 37-40 wt %. The carrier contains anelastomer with a non-polar carbon chain, for example, SBS, SEPS and/orSIS.

The coating liquid can be coated on the carrier by adopting a commoncoating method and device adopted in the art. For example, these methodscomprise rod coating, blade coating, spin coating, roller coating,extruding coating, curtain coating and the like.

The thickness of the coating or binder layer depends on application, forexample is at least about 15 microns. The thickness of the carrier isabove 10 microns, for example 40 microns. The total thickness of thebinder (for example a double face adhesive tape) is below 0.1 mm. Butaccording to application requirements, theses thicknesses can be higheror lower.

Method for Bonding Base Materials and Obtained Assembly

The present disclosure provides a method for removing a bonded basematerial, which comprises the following steps: bonding the binderproduct which can be removed by pulling on at least a part of thesurface of a first base material, wherein, the binder product comprisesa carrier and a binder layer positioned at one side or two oppositesides of the carrier, and the binder layer is formed by curing at leasta part of the binder composition of the present disclosure; andcontacting the second base material with the binder layer to bond asecond base material with the first base material by the binder layer,and leaving a handle capable of being held by a user.

Under the condition that the binder product also comprises an isolationlayer, the method also comprises: before bonding, removing the isolationlayer to expose the binder layer.

The method also comprises pulling by holding the handle, thereby pullingand removing the binder product from the first base material and/or thesecond base material. When a part is repaired and replaced, a part canbe easily detached as required by such pulling removing operation. Anincluded angle between a pulling direction and the surface of the firstbase material and/or the second base material is in a range of 0-90°,for example, more than 35°, more than 50° and more than 70°. Inelectronics industry, due to the limitation of an operation space, alarge pulling removing angle is particularly useful.

The present disclosure also provides an assembly, comprising a firstbase material, a second base material and a binder layer for bonding thefirst base material and the second base material together, wherein thebinder layer is formed by curing at least a part of the bindercomposition of the present disclosure.

The binder of the present disclosure is suitable for a base materialwith low energy (20-35 dyne), and is suitable for a base material withhigh surface energy (higher than 35 dyne). For example, the surfaceenergy of the base material is possibly in a range of 20 dyne to 65dyne. The surface energy can be determined according to an internationalstandard ISO8296.

The presently disclosed binder composition is suitable for the basematerials, comprising: metal, ceramic, polymer, glass and various inksurfaces. Therefore, the presently disclose binder composition can bewidely used in home furnishing, electronic industrial and other fields.Since the presently disclosed binder composition can be removed from abonded base material by pulling, it is particularly suitable forsmartphones, tablet computers and other newly-developing electronicfields, for example, can be used for mounting and detaching (repairingor replacing) of batteries or electronic parts (such as a touch screen).

Without being bound by theory, when selecting the type and ratio of aspecific acrylic acid copolymer, in combination with a flexibilizer anda high-Tg and low-Tg tackifying resin, an acrylic acid binder with awider Tg range can be prepared and can provide excellent bonding forcefor the base materials with different surface energies. By performing180° peeling bonding strength test according to ASTM D3330 (furtherdescribed below), the bonding strength of the presently disclosed bindercomposition is at least 0.5 N/mm, preferably at least 0.7 N/mm, and even1 N/mm or higher. According to an anti-falling performance test (furtherdescribed below), falling height when the binder fails represents thebonding strength, the bonding strength of the presently disclosed bindercomposition can be more than 15 cm, preferably more than 20 cm, and even25 cm, 35 cm or higher.

The binder of the present disclosure has the property of “reducing thebonding strength by pulling (pulling removing performance)”, therefore,the binder can be pulled and removed. The lower the bonding strength ofthe binder in the pulling process is, the harder the adhesive tape isdamaged in a bonding removing process. By performing a pulling strengthtest according to ASTM D3579 (further described below), the breakagepulling strength of the binder of the present disclosure is more than 20MPa, and preferably more than 30 MPa; elongation at break is more than750% and preferably more than 1000%. By performing a viscosity testaccording to PSTC-6 (further described below), the ratio of the initialviscosity of the binder under a non-pulling state to the initialviscosity when the binder is pulled to a strain of 300% is more than 3,preferably more than 5 and even 6 or 7 or higher. According to a pullingremoval test (further described below), the pulling removing ratio ofthe binder of the present disclosure is more than 80%, preferably morethan 90% and 95% and even as high as 100%.

The binder of the present disclosure also has obviously improveddampness/heat/aging resistance. After being aged for 72 hours under thecondition of 65° C. and relative humidity of 95%, the binder of thepresent disclosure can still basically keep the bonding strength andpulling removing performance.

Exemplary embodiments of the present disclosure are described in arepresentative but non-limitative manner. One of skill in the art candesign other various transformed modes and embodiments, which arecovered by the scope and spirit of the present disclosure.

Technical characteristics of respective aspects and respectiveembodiments of the present disclosure can be mutually combined, forexample, respective characteristics related to the binder compositionare correspondingly suitable for the binder product and assembly. Patentdocuments and publications cited by the text are incorporated herein byreference with its all disclosed content, which is similar to the factthat each part is independently incorporated herein. In addition,although some embodiments and parts are numbered with “first” and“second” for description, it should be understood that these numbers areused for facilitating description without implying priority. In thetext, the “binder” and the “binder product” are interchangeable; inaddition, when content percentage is mentioned, the content percentageis based on solid content, namely, the quantity of the solvent is notcalculated.

In the description and claims of the application, “one”, “the”, “said”used in front of certain noun or conditions without obvious quantitycomprise the condition in which more than one referent exists unless thecontent apparently represents other meanings. For example, the conditionthat the composition containing the flexibilizer comprises the conditionthat one or more flexibilizers are used in the composition.

Unless otherwise stated, it should be understood that all numbers forpresenting the feature size, quantity and physical properties used inthe text are modified by the term “about” under all conditions.Therefore, unless otherwise stated, values listed in the description andclaims are all approximate values, those skilled in the art can seek andobtain needed features by using the instruction content disclosed by thetext and properly change these approximate values. In addition, unlessspecifically indicated, a numerical value range represented by endvalues comprise the end values, and all sub ranges and numerical valuesin the range (for example, 20-50 wt % comprising 20 wt %, 30 wt %, 50 wt%, 20-35 wt % and the like).

Unless otherwise indicated, all parts, percentage, ratios and the likein the embodiments and rest parts of the text are calculated accordingto weight.

Following is a listing of non-limiting embodiments according to thepresent disclosure:

Embodiment 1

A binder composition, comprising:

-   -   an acrylic acid copolymer, comprising a (methyl)acrylate monomer        unit and a vinyl carboxylic acid comonomer unit;    -   a flexibilizer, comprising a functional group selected from a        hydroxide radical, a carboxyl group and an amino group, wherein        the flexibilizer has a non-polar carbon chain;    -   a tackifying resin, comprising a high-Tg tackifying resin with a        Tg of at least 20° C. and a low-Tg tackifying resin with a Tg of        not more than 0° C.; and    -   an isocyanate curing agent.

Embodiment 2

The binder composition according to Embodiment 1, wherein a numberaverage molecular weight Mn of the acrylic acid copolymer is lower than500,000 g/mol and the Tg is lower than −30° C.

Embodiment 3

The binder composition according to Embodiment 1, wherein the acrylicacid copolymer comprises the vinyl carboxylic acid copolymer unit in theamount ranging from 3 wt % to 8 wt %.

Embodiment 4

The binder composition according to Embodiment 1, wherein the bindercomposition comprises the acrylic acid copolymer in the amount rangingfrom 20 wt % to 50 wt %.

Embodiment 5

The binder composition according to Embodiment 1, wherein the non-polarcarbon chain of the flexibilizer is derived from unsaturated alkene.

Embodiment 6

The binder composition according to Embodiment 1, wherein theflexibilizer comprises the combination of hydroxy-terminatedpolybutadiene and SBS rubber.

Embodiment 7

The binder composition according to Embodiment 6, wherein a hydroxylcontent of the hydroxy-terminated polybutadiene is at least 1 mmol/g.

Embodiment 8

The binder composition according to Embodiment 6, wherein a numberaverage molecular weight Mn of the hydroxy-terminated polybutadiene isbetween 2300 g/mol and 4500 g/mol.

Embodiment 9

The binder composition according to Embodiment 6, wherein thehydroxyl-terminated polybutadiene is present in an amount ranging from20 wt % to 50 wt % based on the weight of the acrylic acid copolymer.

Embodiment 10

The binder composition according to Embodiment 6, wherein the bindercomposition comprises the SBS rubber in an amount ranging from 5 wt % to35 wt %.

Embodiment 11

The binder composition according to Embodiment 1, wherein the bindercomposition comprises the flexibilizer in an amount of not more than 65wt %.

Embodiment 12

The binder composition according to Embodiment 11, wherein the bindercomposition comprises the flexibilizer in an amount ranging from 10 wt %to 65 wt %.

Embodiment 13

The binder composition according to Embodiment 1, wherein the Tg of thehigh-Tg tackifying resin is at least 85° C. and the Tg of the low-Tgtackifying resin is not more than −20° C.

Embodiment 14

The binder composition according to Embodiment 1, wherein a weight ratioof the high-Tg tackifying resin to the low-Tg tackifying resin rangesfrom 1:1 to 8:1.

Embodiment 15

The binder composition according to Embodiment 1, wherein a weight ratioof the high-Tg tackifying resin to the low-Tg tackifying resin rangesfrom 2:1 to 4:1.

Embodiment 16

The binder composition according to Embodiment 1, wherein the bindercomposition comprises the tackifying resin in an amount ranging from 30wt % to 45 wt %.

Embodiment 17

The binder composition according to Embodiment 1, wherein the isocyanatecuring agent is present in an amount ranging from more than 0 wt % tonot more than 3 wt % based on the weight of the acrylic acid copolymer.

Embodiment 18

The binder composition according to Embodiment 6, the isocyanate curingagent is present in an amount of at least 5 wt % based on the weight ofthe hydroxy-terminated polybutadiene.

Embodiment 19

The binder composition according to any one of Embodiments 1 to 18,comprising: the acrylic acid copolymer in an amount ranging from 20 wt %to 50 wt %, the flexibilizer in an amount ranging from 10 wt % to 65 wt%, the tackifying resin in the amount ranging from 30 wt % to 45 wt %,and the isocyanate curing agent in the amount ranging from more than 0wt % to not more than 3 wt % based on the weight of the acrylic acidcopolymer.

Embodiment 20

A binder product, comprising a binder layer formed by curing at least apart of the binder composition in any one of Embodiments 1 to 19.

Embodiment 21

The binder product according to Embodiment 20, further comprising:

a carrier, wherein the binder layer is disposed on one side of thecarrier, or the binder layers are respectively disposed on two opposingsides of the carrier; and

-   -   an isolation layer optionally covering an exposed surfaced of        the binder layer.

Embodiment 22

The binder product according to Embodiment 21, wherein the carriercontains an elastomer with a non-polar carbon chain.

Embodiment 23

The binder product according to Embodiment 22, wherein the elastomer isselected from SBS, SEPS, SIS and isocyanate-crosslinkedhydroxy-terminated polybutadiene.

Embodiment 24

The binder product according to Embodiment 20, wherein when a test isperformed according to an initial viscosity test standard PSTC-6, aratio of an initial viscosity of the binder product under a non-pullingstate to an initial viscosity when the binder product is pulled to astrain of 300% is more than 3.

Embodiment 25

The binder product according to Embodiment 20, wherein when a test isperformed according to an initial viscosity test standard PSTC-6, aratio of an initial viscosity of the binder product under a non-pullingstate to an initial viscosity when the binder product is pulled to astrain of 300% is more than 5.

Embodiment 26

The binder product according to Embodiment 24, wherein after being agedfor 72 hours under the condition of 65° C. and relative humidity of 95%,a test is performed according to an initial viscosity test standardPSTC-6, and a ratio of an initial viscosity of the binder product undera non-pulling state to an initial viscosity when the binder product ispulled to a strain of 300% is more than 2.4.

Embodiment 27

The binder product according to Embodiment 25, wherein after being agedfor 72 hours under the condition of 65° C. and relative humidity of 95%,a test is performed according to an initial viscosity test standardPSTC-6, and a ratio of an initial viscosity of the binder product undera non-pulling state to an initial viscosity when the binder product ispulled to a strain of 300% is kept more than 5.

Embodiment 28

A method for preparing a binder product, comprising following steps:

-   -   providing the binder composition according to any one of        Embodiments 1 to 19 positioned in a liquid medium, and obtaining        a coating liquid;    -   coating the coating liquid on one side or two opposite sides of        a carrier, and forming a coating; and    -   curing at least a part of the coating and forming a binder        layer.

Embodiment 29

The method according to Embodiment 28, wherein the liquid medium isselected from an organic inert solvent and the carrier comprises anelastomer with a non-polar carbon chain.

Embodiment 30

An adhesive tape, comprising:

a carrier containing an elastomer, and

a binder layer disposed on one side or two opposing sides of thecarrier, the binder layer is formed by the binder composition and thebinder composition comprises:

-   -   an acrylic acid copolymer in an amount ranging from 20 wt % to        50 wt %, comprising a (methyl)acrylate monomer unit and a vinyl        carboxylic acid comonomer unit in an amount ranging from 3 wt %        to 8 wt %;    -   a flexibilizer in an amount ranging from 10 wt % to 65 wt %,        comprising a combination of hydroxy-terminated polybutadiene and        SBS rubber;    -   a tackifying resin in an amount ranging from 30 wt % to 45 wt %,        comprising a high-Tg tackifying resin with a Tg of at least        20° C. and a low-Tg tackifying resin with a Tg of not more than        0° C., wherein a weight ratio of the high-Tg tackifying resin        and the low-Tg tackifying resin ranges from 1:1 to 1:8; and    -   an isocyanate curing agent, wherein the isocyanate curing agent        is present in an amount of not more than 3 wt % of the weight of        the acrylic acid copolymer and in an amount that is least 5 wt %        of the weight of the hydroxy-terminated polybutadiene.

Embodiment 31

The adhesive tape according to Embodiment 30, wherein the acryliccopolymer has a number average molecular weight Mn lower than 500,000g/mol and a Tg lower than −30° C.

Embodiment 32

The adhesive tape according to Embodiment 30 or 31, wherein a hydroxylcontent of the hydroxy-terminated polybutadiene is between 1 mmol/g to1.5 mmol/g, number average molecular weight ranges from 2300 g/mol to4500 g/mol, and the hydroxyl-terminated polybutadiene is present in anamount ranging from 20 wt % to 50 wt % based on the weight of theacrylic acid copolymer;

wherein the binder composition comprises the SBS rubber in an amountranging from 5 wt % to 35 wt %.

Embodiment 33

The adhesive tape according to any one of Embodiments 30 to 32, whereinthe Tg of the high-Tg tackifying resin is at least 85° C. and the Tg ofthe low-Tg tackifying resin is not more than −20° C., and a weight ratioof the high-Tg tackifying resin to the low-Tg tackifying resin rangesfrom 2:1 to 4:1.

Embodiment 34

The adhesive tape according to any one of Embodiments 30 to 33, whereinthe elastomer is selected from SBS, SEPS, SIS and isocyanate-crosslinkedhydroxy-terminated polybutadiene.

Embodiment 35

An assembly, comprising a first base material, a second base materialand a binder layer for bonding the first base material and the secondbase material together, wherein the binder is formed by curing at leasta part of the binder composition according to one of Embodiments 1 to19.

Embodiment 36

The assembly according to Embodiment 35, wherein, the first basematerial and the second base material are respectively independentlyselected from low surface energy base materials with a surface energyranging from 20dyne to 35 dyne and high surface energy base materialswith a surface energy higher than 35 dyne.

Embodiment 37

The assembly according to Embodiment 35, wherein the first base materialand the second base material are respectively independently selectedfrom metal, ceramic, polymer, glass and ink surface.

Embodiment 38

The assembly according to any one of Embodiments 35 to 37, wherein thebinder layer can be removed from the first base material and/or thesecond base material by pulling.

EXAMPLES

Test Method

Pulling strength test: the pulling strength test is performed accordingto an international standard ASTM D3759, the instrument for the test isan Instron (4465 type) pulling instrument, a chuck speed is 304.8mm/min, and the size of a binder sample is 12.7 mm*25.4 mm.

180° peeling bonding strength test: the 180° peeling bonding strengthtest is performed according to an international standard ASTM D3330, theinstrument for the test is an IMASS SP-200 sliding/peeling tester(obtained from IMASS, Inc., Accord, Mass.), the test speed is 12inch/min.

Initial viscosity test: according to a test standard PSTC-6, a rollingball method is adopted for the initial viscosity test (measuring surfaceviscosity). Main instruments for test comprise: a slope, a steel balland a regular stainless base material. The steel ball of 5.6 g (diameterbeing 11 mm) rolls onto a binder sample along the slope (height: 65 mm,slant angle: 21.5°). As the binder has a bonding function and obstructsrolling of the steel ball till stopping rolling of the steel ball. Thedistance that the steel ball rolls on the surface of the binder sample(called as “steel ball rolling distance” below) is used for measuringthe initial viscosity. Therefore, the initial viscosity is inverselyproportional to the steel ball rolling distance.

The steel ball rolling distances of the binder sample at the initialstate and when being pulled to the strain of 300% are respectivelytested and are respectively marked as L_(ini) and L_(300%). Therefore,the ratio of the initial viscosity of the binder under a non-pullingstate to the initial viscosity when the binder is pulled to a strain of300% is L_(300%)/L_(ini).

Pulling removing performance test: two test blocks are bonded by using abinder sample of 90 mm*20 mm*0.1 mm (length*width*height), a handle isleft, an Instron (4465 type) pulling instrument is adopted to performthe pulling removing performance test on the binder sample under thecondition that the chuck speed is 12 inch/min at a pulling angle of 90°.The pulling removing reliability is measured by the percentage (%) of acompletely removed sample relative to the total tested sample. In theembodiments, the pulling removing performance test is performed undertwo conditions respectively: 1) an original sample; 2) a sample which isaged for 72 hours under the condition of 65° C. and relative humidity(RH) of 95%.

Anti-falling performance test: a device as shown in FIG. 2 is adopted,and a binder sample of 60 mm*20 mm is adopted to perform theanti-falling performance test. The device comprises a base 1, a supportrod 2 supported by the base 1, and a support block 6 positioned at thetop end of the support rod 2, a bottom plate 3 is fixed on the supportblock 6 by fixing screws 7, and 4 weights of 0.5 Kg are bonded on thebottom plate 3 by the binder sample. Beginning from an initial height of5 cm, the falling height is increased step by step by an increment of 5cm every time, the height of failure (short for HOFF) when the sample isfailed is observed. If any part of the binder sample showsfailure/peeling, the failure is determined.

Material Instruction

The material used by the following embodiments and comparative examplesis as follows:

Material Instruction Sk-Dyne 1717 DT acrylic acid copolymer, obtainedfrom Soken Kagaku Qilong HTPB hydroxy-terminated polybutadiene, Mn:2300:2800, hydroxy group content: 1 mmol/g, obtained from QilongChemical RegaliteC8010 Hydrogenated liquid HC resin, obtained fromEastman Kraton D1101K SBS, containing polystyrene block of 16% anddiblock of about 31 wt %, obtained from Kraton Piccolyte A135 terpeneresin, softening point: 135° C., obtained from PINOVA Desmodur L-75 TDIcrosslinking agent, obtained from Bayer Thermogrip H2187 SBS resin,obtained from Bostik Kraton G1657 SEBS, containing polystyrene block of13% and diblock of about 36 wt %, obtained from Kraton Kraton G1650SEBS, containing polystyrene block of 30% and no diblock, obtained fromKraton Regalite S 1100 Partially hydrogenated liquid HC resin, softeningpoint: 100° C., 100 obtained from Eastman Regalite R 1010 Hydrogenatedliquid HC resin, obtained from Eastman

Embodiments 1-6

According to constitution of Table 1, binder samples of the embodiments1-6 are prepared. A preparation process of these binder samples is asfollows: besides the TDI crosslinking agent, the rest components areadded in a glass wild-mouth bottle; methylbenzene is added to prepare asolution with the solid content of 37-40%, the wild-opening bottle isplaced on a roller overnight for mixing; before coating, an isocyanatecrosslinking agent is added into the wild-opening bottle, and uniformmixing is performed to obtain coating liquid; the coating liquid iscoated on upper and lower sides of an SBS carrier (D1101K, obtained fromKraton, US) which is 40 microns thick by a blade coating machine whichis 15 cm wide, and intervals of the coating machine are set, so thatbinder layers which are 30 microns thick are formed at each side afterdrying; the samples are placed in an oven, and are dried for 10-15minutes under 90° C. to obtain a binder sample which is an adhesive tapewith the total thickness of 100 microns. Before test, the binder sampleis covered by an isolation lining (PCK release paper coated withpolyethylene), and is preserved in a room of 23° C. and RH of 50% for 24hours, then the isolation lining is peeled for performance test.

TABLE 1 constitution of binder Material (wt %)/ embodiments 1 2 3 4 5 6Sk-Dyne 1717 DT 50 20 40 20 15 40 Qilong HTPB 10 10 10 10 5.25 14.75Regalite C8010 10 10 20 5 5 10 Kraton D1101K 5 0 5 0 0 10 Piccolyte A13524.5 24.5 24.5 24.5 24.5 24.5 Desmodur L-75 0.5 0.5 0.5 0.5 0.25 0.75Thermogrip H2187 0 35 0 40 50 0

The binder samples of the embodiments 1-6 are tested according to thetest method described above, and a test result is as shown in Table 2and Table 3 below.

Comparative Example 1

According to the manner described in embodiments 1-6, by adopting aformula in patent document US2008/0271846A1, Kraton G1657 of 70 g,Kraton G1650 of 30 g, Regalite S1100 of 65 g and Regalite R1010 of 85 gare prepared into a binder sample of the comparative example 1. Test isperformed according to a method same as that in the embodiments 1-6, andthe test result is as shown in Table 2 and Table 3 below

TABLE 2 main performance indexes of the binder at room temperaturePulling removing performance test Rolling force(N)/ 180° peeling balltest reliability(%) HOFF Pulling Elon- bonding strength test mm LSE +HSE + cm strength gation N/mm L_(300%)/ AA AA LSE + HSE + Examples MPa %SS AA LSE HSE L_(ini) L_(300%) L_(ini) N % N % AA AA Embodiment 1 31.51105 1.1 0.89 0.81 1.03 4 27 6.75 5.5 100 5.8 100 35 45 Embodiment 2 351080 0.93 0.74 0.75 0.81 5 38 7.6 4.117 100 4.367 100 25 30 Embodiment 320 1100 0.91 0.75 0.66 0.8 3 9 3 5.1 80 5.3 80 15 30 Embodiment 4 41.75750 0.65 0.51 0.53 0.623 8 35 4.375 4.65 100 4.886 100 15 15 Embodiment5 32 820 0.5 0.42 0.67 0.45 9 45 5 4.2 80 3.6 80 10 5 Embodiment 6 351250 1 0.85 0.9 0.95 4 34 8.5 4.3 100 4.5 100 40 45 Comparative 15 13000.8 0.7 0.65 0.8 5 35 7 3.2 100 3.1 100 15 15 example 1

TABLE 3 main performance indexes of the binder after aging for 72 hoursat high temperature and high humidity conditions (65° C., RH of 90%)Pulling removing performance test Rolling force(N)/ 180° peeling balltest reliability(%) HOFF Pulling Elon- bonding strength test mm LSE +HSE + cm strength gation N/mm L_(300%)/ AA AA LSE + HSE + Examples MPa %SS AA LSE HSE L_(ini) L_(300%) L_(ini) N % N % AA AA Embodiment 1 27.51008 1.2 0.95 0.83 1.3 3 21 7.00 4.3 90 4.7 90 35 40 Embodiment 2 34.25980 1.01 0.87 0.8 0.93 4 35 8.75 3.6 100 3.65 100 25 35 Embodiment 316.75 930 0.96 0.79 0.67 0.9 3 7.3 2.43 3.3 60 3.75 50 20 30 Embodiment4 37.5 565 0.76 0.58 0.55 0.732 7 33 4.71 4.6 75 4.7 70 15 15 Embodiment5 28 670 0.55 0.4 0.72 0.5 8 36 4.5 4.5 50 3.6 70 10 10 Embodiment 6 331090 1.1 0.9 1.1 1 4 32 8 4.5 100 4.5 100 45 45 Comparative 9 900 0.850.73 0.7 0.9 5 24 4.8 3.5 50 3.5 40 15 15 example 1 Noted: in Tables2-3, SS: stainless steel; AA: anodized aluminum; LSE: low surface energybase material (30-35 dyne); HSE: high surface-energy base material(55-65 dyne), printing ink surface

As shown in above tables, respective embodiments all have better bondingstrength for base materials with high and low surface energies (as shownin the 180° peeling bonding strength test) and better anti-fallingperformance, show pulling strength superior to that of the comparativeexample 1, are still the same even after the severe aging testconditions. Meanwhile, they can be very easily pulled and removed (asshown in the rolling ball test result), the initial viscosity undercertain pulling strain is obviously reduced, and the binder samples ofthe present disclosure show the pulling removing performance superior tothat of the comparative example 1.

Therefore, the acrylic acid binder is suitable for bonding various basematerials, comprising low-surface energy base materials and high-surfaceenergy materials. The binder can provide sufficient bonding strength andthe bonding strength thereof can be obviously reduced by pulling, sothat in a pulling process, the bonding strength is reduced, pullingremoving is easy to realize, and pulling bonding removal can berealized. In addition, the binder of the present disclosure also has theobviously improved aging resistance.

It will be obvious for those skilled in the art that variousmodifications and variations can be made to the present disclosure,without departing from the scope and spirit thereof.

1. A binder composition, comprising: an acrylic acid copolymer,comprising a (methyl)acrylate monomer unit and a vinyl carboxylic acidcomonomer unit; a flexibilizer, comprising a functional group selectedfrom a hydroxide radical, a carboxyl group and an amino group, whereinthe flexibilizer has a non-polar carbon chain; a tackifying resin,comprising a high-Tg tackifying resin with a Tg of at least 20° C. and alow-Tg tackifying resin with a Tg of not more than 0° C.; and anisocyanate curing agent.
 2. The binder composition according to claim 1,wherein a number average molecular weight Mn of the acrylic acidcopolymer is lower than 500,000 g/mol and the Tg is lower than −30° C.3. The binder composition according to claim 1, wherein the acrylic acidcopolymer comprises the vinyl carboxylic acid copolymer unit in theamount ranging from 3 wt % to 8 wt %.
 4. The binder compositionaccording to claim 1, wherein the binder composition comprises theacrylic acid copolymer in the amount ranging from 20 wt % to 50 wt %. 5.The binder composition according to claim 1, wherein the non-polarcarbon chain of the flexibilizer is derived from unsaturated alkene. 6.The binder composition according to claim 1, wherein the flexibilizercomprises the combination of hydroxy-terminated polybutadiene and SBSrubber.
 7. The binder composition according to claim 6, wherein ahydroxyl content of the hydroxy-terminated polybutadiene is at least 1mmol/g.
 8. The binder composition according to claim 6, wherein a numberaverage molecular weight Mn of the hydroxy-terminated polybutadiene isbetween 2300 g/mol and 4500 g/mol.
 9. The binder composition accordingto claim 6, wherein the hydroxyl-terminated polybutadiene is present inan amount ranging from 20 wt % to 50 wt % based on the weight of theacrylic acid copolymer.
 10. The binder composition according to claim 6,wherein the binder composition comprises the SBS rubber in an amountranging from 5 wt % to 35 wt %.
 11. The binder composition according toclaim 1, wherein the binder composition comprises the flexibilizer in anamount of not more than 65 wt %.
 12. The binder composition according toclaim 11, wherein the binder composition comprises the flexibilizer inan amount ranging from 10 wt % to 65 wt %.
 13. The binder compositionaccording to claim 1, wherein the Tg of the high-Tg tackifying resin isat least 85° C. and the Tg of the low-Tg tackifying resin is not morethan −20° C.
 14. The binder composition according to claim 1, wherein aweight ratio of the high-Tg tackifying resin to the low-Tg tackifyingresin ranges from 1:1 to 8:1.
 15. The binder composition according toclaim 1, wherein a weight ratio of the high-Tg tackifying resin to thelow-Tg tackifying resin ranges from 2:1 to 4:1.
 16. The bindercomposition according to claim 1, wherein the binder compositioncomprises the tackifying resin in an amount ranging from 30 wt % to 45wt %.
 17. The binder composition according to claim 1, wherein theisocyanate curing agent is present in an amount ranging from more than 0wt % to not more than 3 wt % based on the weight of the acrylic acidcopolymer.
 18. The binder composition according to claim 6, theisocyanate curing agent is present in an amount of at least 5 wt % basedon the weight of the hydroxy-terminated polybutadiene.
 19. The bindercomposition according to claim 1, comprising: the acrylic acid copolymerin an amount ranging from 20 wt % to 50 wt %, the flexibilizer in anamount ranging from 10 wt % to 65 wt %, the tackifying resin in theamount ranging from 30 wt % to 45 wt %, and the isocyanate curing agentin the amount ranging from more than 0 wt % to not more than 3 wt %based on the weight of the acrylic acid copolymer.
 20. A binder product,comprising a binder layer formed by curing at least a part of the bindercomposition in claim
 1. 21. The binder product according to claim 20,further comprising: a carrier, wherein the binder layer is disposed onat least one side of the carrier.
 22. The binder product according toclaim 21, wherein the carrier contains an elastomer with a non-polarcarbon chain.
 23. The binder product according to claim 22, wherein theelastomer is selected from SBS, SEPS, SIS and isocyanate-crosslinkedhydroxy-terminated polybutadiene.
 24. The binder product according toclaim 20, wherein when a test is performed according to an initialviscosity test standard PSTC-6, a ratio of an initial viscosity of thebinder product under a non-pulling state to an initial viscosity whenthe binder product is pulled to a strain of 300% is more than
 3. 25. Thebinder product according to claim 20, wherein when a test is performedaccording to an initial viscosity test standard PSTC-6, a ratio of aninitial viscosity of the binder product under a non-pulling state to aninitial viscosity when the binder product is pulled to a strain of 300%is more than
 5. 26. The binder product according to claim 24, whereinafter being aged for 72 hours under the condition of 65° C. and relativehumidity of 95%, a test is performed according to an initial viscositytest standard PSTC-6, and a ratio of an initial viscosity of the binderproduct under a non-pulling state to an initial viscosity when thebinder product is pulled to a strain of 300% is more than 2.4.
 27. Thebinder product according to claim 25, wherein after being aged for 72hours under the condition of 65° C. and relative humidity of 95%, a testis performed according to an initial viscosity test standard PSTC-6, anda ratio of an initial viscosity of the binder product under anon-pulling state to an initial viscosity when the binder product ispulled to a strain of 300% is kept more than
 5. 28. A method forpreparing a binder product, comprising following steps: providing thebinder composition according to claim 1 positioned in a liquid medium,and obtaining a coating liquid; coating the coating liquid on one sideor two opposite sides of a carrier, and forming a coating; and curing atleast a part of the coating and forming a binder layer.
 29. The methodaccording to claim 28, wherein the liquid medium is selected from anorganic inert solvent and the carrier comprises an elastomer with anon-polar carbon chain.
 30. An adhesive tape, comprising: a carriercontaining an elastomer, and a binder layer disposed on one side or twoopposing sides of the carrier, the binder layer is formed by the bindercomposition and the binder composition comprises: an acrylic acidcopolymer in an amount ranging from 20 wt % to 50 wt %, comprising a(methyl)acrylate monomer unit and a vinyl carboxylic acid comonomer unitin an amount ranging from 3 wt % to 8 wt %; a flexibilizer in an amountranging from 10 wt % to 65 wt %, comprising a combination ofhydroxy-terminated polybutadiene and SBS rubber; a tackifying resin inan amount ranging from 30 wt % to 45 wt %, comprising a high-Tgtackifying resin with a Tg of at least 20° C. and a low-Tg tackifyingresin with a Tg of not more than 0° C., wherein a weight ratio of thehigh-Tg tackifying resin and the low-Tg tackifying resin ranges from 1:1to 1:8; and an isocyanate curing agent, wherein the isocyanate curingagent is present in an amount of not more than 3 wt % of the weight ofthe acrylic acid copolymer and in an amount that is least 5 wt % of theweight of the hydroxy-terminated polybutadiene.
 31. The adhesive tapeaccording to claim 30, wherein the acrylic copolymer has a numberaverage molecular weight Mn lower than 500,000 g/mol and a Tg lower than−30° C.
 32. The adhesive tape according to claim 30, wherein a hydroxylcontent of the hydroxy-terminated polybutadiene is between 1 mmol/g to1.5 mmol/g, number average molecular weight ranges from 2300 g/mol to4500 g/mol, and the hydroxyl-terminated polybutadiene is present in anamount ranging from 20 wt % to 50 wt % based on the weight of theacrylic acid copolymer; wherein the binder composition comprises the SBSrubber in an amount ranging from 5 wt % to 35 wt %.
 33. The adhesivetape according to claim 30, wherein the Tg of the high-Tg tackifyingresin is at least 85° C. and the Tg of the low-Tg tackifying resin isnot more than −20° C., and a weight ratio of the high-Tg tackifyingresin to the low-Tg tackifying resin ranges from 2:1 to 4:1.
 34. Theadhesive tape according to claim 30, wherein the elastomer is selectedfrom SBS, SEPS, SIS and isocyanate-crosslinked hydroxy-terminatedpolybutadiene.
 35. An assembly, comprising a first base material, asecond base material and a binder layer for bonding the first basematerial and the second base material together, wherein the binder isformed by curing at least a part of the binder composition according toThe adhesive tape according to claim
 1. 36. The assembly according toclaim 35, wherein, the first base material and the second base materialare respectively independently selected from low surface energy basematerials with a surface energy ranging from 20 dyne to 35 dyne and highsurface energy base materials with a surface energy higher than 35 dyne.37. The assembly according to claim 35, wherein the first base materialand the second base material are respectively independently selectedfrom metal, ceramic, polymer, glass and ink surface.
 38. The assemblyaccording to claim 35, wherein the binder layer can be removed from thefirst base material and/or the second base material by pulling.